First direct evidence for inflation

[Silvertusk]

http://news.nationalgeographic.com/news ... nce-space/

Dr Hana - could you possible explain whether it is feasible or not what they talk about in the article?

[Ivellious]

Interesting. I admit, most of this stuff is well over my head (physics was never my thing, and certainly not this crazy cosmic-level physics), so I don't totally get how this latest gravitational wave data leads to evidence for a multiverse. But even then, that article is mostly referring to old news about multiverse theory...basically, that some scientists believe that a multiverse might be the explanation for some of the things we observe in nature. The beginning paragraphs mention the new discovery, but don't really explain much about it after that.

[Silvertusk]

Here is another article.

http://www.nytimes.com/2014/03/18/scien ... .html?_r=0

What is particularly interesting is this quote:

Confirming inflation would mean that the universe we see, extending 14 billion light-years in space with its hundreds of billions of galaxies, is only an infinitesimal patch in a larger cosmos whose extent, architecture and fate are unknowable. Moreover, beyond our own universe there might be an endless number of other universes bubbling into frothy eternity, like a pot of pasta water boiling over.

[Philip]

"... some scientists believe that a multiverse might be the explanation for some of the things we observe in nature."

The entire idea of the multiverse is simply conjecture and not validated by current science. PLUS, even IF multiple CHAINS of universes existed, there STILL would have to be a beginning to them. So to say our present universe isn't the only one to have existed is merely to kick the can down the cosmic road, as EVERYTHING has a cause and a beginning. Yes, the question is what or WHO is the source of singularity - the expansion is another issue entirely.

But let's not forget that the expansion and instant creation of time, matter, energy, dimension and the resulting expansion/inflation were in no way random, as they were all part of a precision that brought us the present universe and eventually resulted in our planet's qualities that allowed and sustained life. AND the very physical/astronomical/chemical laws that guided that expansion WERE PRESENT AT THE VERY BEGINNING. Such laws nor the universe they guided can create themselves.

I do believe there may well have been other universes, yet UNconnected via pure randomness or natural phenomena as non-theists believe a multiverse would be. If they exist/existed, God may have independently created such universes. God is eternal. For Him, 14 billion years ago was just enough time for an afternoon nap in heaven. As one of the very characteristics of God is that He is constantly active, in control and creative, tells me that I shouldn't be surprised if He has created other universes in the past - perhaps independently, unconnected, with beginnings and endings. Or perhaps that even STILL exist, but unconnected and invisible to our present universe or in other dimensions. Our Bible tells us what God wants to communicate to US, what is useful and relevant to US. Of course, we also could be the ONLY universe God has created. So one universe or multiple universes are possibilities, just not interconnected per non-theistic randomness/naturalism.

Similarly, I believe that God MAY have created other life in other places in our universe. If so, likely so remote from us that we will likely never be able to detect or communicate with it (if such life is intelligent enough to do so). I think if we were meant to ever come into contact with other life in our universe, that God either would have or still will prepare us for that. So, discovering other life in our universe shouldn't cause us any theological problems but it would pose many questions. That God is omnipresent would mean that He could live amongst us in Heaven forever, but also be present elsewhere (in other places, dimensions, times).

[1over137]

Hmm, from what I have read, it seems that currently the best theories cosmologists have are multiverse theories. But I need to search more about this.

Interesting article is this one (i have to look what "single slow-rolling scalar field" theory is)

http://blogs.scientificamerican.com/gue ... -now-what/

Here is some quote from it:

If BICEP2 is proven correct, it should lead to at least one Nobel Prize. Further down the road, I bet that a first-ever satellite designed specifically to measure inflationary gravitational waves will get funded (now that we know there’s a signal for it to measure), which can determine how the cosmic doubling rate during inflation changed with time. This provides a great way to distinguish between specific inflation models and also to test any inflation competitors that may have gained credibility by then (for example, string gas models predict an increase whereas all inflation models predict a decrease).

But first, let’s celebrate one of the most exciting moments in the history of science! Above all, this feels like a great triumph for Occam’s razor: although countless complicated models for inflation emerged over the years, the BICEP2 data is beautifully fit by simple “classic’’ inflation, known in geek-speak as a single slow-rolling scalar field. And Andrei Linde looked particularly happy at the press conference, perhaps because two numbers have now been measured that act as a sort of fingerprint of inflation models: n=0.9608±0.0054 (reported by Planck, quantifying the ratio of small to large spots in the baby pictures) and r=0.16±0.05 (reported by BICEP2, quantifying the gravitational wave amplitude after correcting for galactic radio noise). These measurements agree tantalizingly well with the specific predictions of what’s arguably the simplest model of all: Andrei’s own favorite, whose potential energy curve is a simple parabola, which predicts n=0.96 and r=0.15. I think William of Occam would have been impressed!

[Silvertusk]

Good old WLC. I can always rely on him:

http://www.reasonablefaith.org/new-evid ... -inflation

[1over137]

Good old WLC. I can always rely on him:

http://www.reasonablefaith.org/new-evid ... -inflation

Thanks for the link in which there is link to video I hope to find more information in, especially references.

[Byblos]

Good old WLC. I can always rely on him:

http://www.reasonablefaith.org/new-evid ... -inflation

I agree with WLC's conclusion on 1). On 2), however, he is wrong.

As for Linde’s multiverse comment, inflation alone does not guarantee a multiverse. It all depends on the properties of the initial field responsible for inflation, about which we can only speculate. There may be other inflating universes, or there may not.

Not true. Linde seems to be correct insomuchas wherever inflation exists, the multiverse exists not only due to the fact that inflation is future eternal, but also because the rate of decay is slower than the rate of expansion. The way I understand it, when inflation reaches its half-life decay, a universe is banged. But because the expansion rate is much faster than the decay rate, there will be an infinite number of half-lives and therefore, an infinite number of universes banged.

What’s important to keep in mind is: (i) Theology has no reason to deny that God may have created a wider reality than just our universe.

Very true.

(ii) Inflationary models may be future-eternal (they will go on forever), but they cannot be past eternal (the multiverse itself had a beginning). Attempts to make the multiverse past-eternal (like Sean Carroll’s model) fail for a variety of reasons.

Also true as per the BVG theorm. Although in one lecture Alan Guth (who's one third of the BVG theorem) intimated that it is theoretically possible for a universe to arise out of zero-sum energy state.

(iii) Multiverse scenarios face the troublesome Boltzmann brain problem. A finely-tuned universe like ours is incomprehensibly improbable on naturalism. The more you multiply worlds within the multiverse in order to make it likely that observers will appear somewhere in the multiverse of worlds, the more probable it becomes that we should be Boltzmann brains, isolated brains which have fluctuated into existence out of the quantum vacuum. For observable worlds like that are vastly more plenteous than worlds which are fine-tuned for embodied conscious agents. So if we were just random members of a multiverse of worlds, we ought to have observations like that. But we don’t; which disconfirms the multiverse hypothesis.

Not true. In the inflationary model the apparent fine-tuning is actually predicted by the theory and is due to negative (repulsive) gravity (yes, there is such a thing and it was also predicted by Einstein's theory of general relativity). This is where the physics get a little complicated, they have to do with the cosmological constant, which in our universe is calculated to be = 1 with a precision of 16 decimals (meaning our universe is highly ordered). How can these conditions be such at the big bang? Well, it so happens that negative gravity in the inflationary model actually converges the cosmological constant onto 1 instead of driving it away from 1 in any direction.

[Silvertusk]

Sorry Byblos dont understand this bit at all.

Not true. Linde seems to be correct insomuchas wherever inflation exists, the multiverse exists not only due to the fact that inflation is future eternal, but also because the rate of decay is slower than the rate of expansion. The way I understand it, when inflation reaches its half-life decay, a universe is banged. But because the expansion rate is much faster than the decay rate, there will be an infinite number of half-lives and therefore, an infinite number of universes banged.

[Silvertusk]

or this bit for that matter

Not true. In the inflationary model the apparent fine-tuning is actually predicted by the theory and is due to negative (repulsive) gravity (yes, there is such a thing and it was also predicted by Einstein's theory of general relativity). This is where the physics get a little complicated, they have to do with the cosmological constant, which in our universe is calculated to be = 1 with a precision of 16 decimals (meaning our universe is highly ordered). How can these conditions be such at the big bang? Well, it so happens that negative gravity in the inflationary model actually converges the cosmological constant onto 1 instead of driving it away from 1 in any direction.

[Silvertusk]

So this is where I am thrown and it is really bothering me.

On the one hand we have Theists excited about this discovery because it cements the big bang and therefore proves the universe had a beginning. On the other hand you have the Atheists excited because it opens the door to a multiverse and therefore this removes the need for a creator as it solves the fine tuning argument.

So to be honest I need someone to lay it out in laymans terms to explain to me is this evidence for or against God and should we be worried.

Help please as it is really put up a wall for me.

Silvertusk.

[Byblos]

So this is where I am thrown and it is really bothering me.

On the one hand we have Theists excited about this discovery because it cements the big bang and therefore proves the universe had a beginning. On the other hand you have the Atheists excited because it opens the door to a multiverse and therefore this removes the need for a creator as it solves the fine tuning argument.

So to be honest I need someone to lay it out in laymans terms to explain to me is this evidence for or against God and should we be worried.

Help please as it is really put up a wall for me.

Silvertusk.

Like I said in your thread, even if proven true a multiverse does not disprove a first cause since even the multiverse must have a starting point in the past (it is not past eternal, only future eternal).

Let's talk about the inflationary model first, what is it and what does it predict. According to Alan Guth, the father of the inflationary model, inflation is what put the bang in the big bang. It describes the prequel to the big bang. The theory postulates that repulsive gravity caused the initial conditions of the universe to expand with extreme velocity, on the order of 100 times faster than the speed of light. When repulsive gravity reaches its half life, it causes a bang, and poof a universe pops out. But because of the speed, this process doesn't stop, it repeats itself eternally, albeit with each half-life cycle being less frequent.

The theory also predicts a very highly ordered initial conditions due to the nature of repulsive gravity and its reverse impact on the cosmological constant. I know I still owe you the a detailed explanation of this, I will get to it at some point but first I have to spend about an 1.5 hours reviewing relevant material.

What does the inflationary model NOT say anything about.

- It says nothing about what came prior to the prequel of the big bang (prior to the initial repulsive gravity conditions)
- It says nothing about the number of universes that can potentially pop out
- It says nothing about the type of universes that can potentially pop out and what laws of physics they will produce (which may or may not be different than ours)
- It says nothing about the anthropic potentiality of each of these universes (whether or not they have the potential to produce life, any kind of life, let alone the intelligent kind capable of discovering such wonderful laws)
- And most importantly, it says absolutely nothing on the need for a first cause because that's a metaphysical premise, not a scientific one.

[Silvertusk]

Thank you Byblos, your explanations are starting to make things clearer.

So when you say that the repulsive gravity was making the universe expand - I take it you are talking about the preexisting universe (or the space) that existed before our universe came into existence?

Silvertusk.

[Byblos]

Thank you Byblos, your explanations are starting to make things clearer.

So when you say that the repulsive gravity was making the universe expand - I take it you are talking about the preexisting universe (or the space) that existed before out universe came into existence?

Silvertusk.

Essentially yes, but I wouldn't call it space since space-time is a direct result of the big bang so it cannot precede it. The consensus is that it's some kind of quantum gravitational field. In other words, it's not nothing and we still don't know what caused it.

[Silvertusk]

Thank you Byblos, your explanations are starting to make things clearer.

So when you say that the repulsive gravity was making the universe expand - I take it you are talking about the preexisting universe (or the space) that existed before out universe came into existence?

Silvertusk.

Essentially yes, but I wouldn't call it space since space-time is a direct result of the big bang so it cannot precede it. The consensus is that it's some kind of quantum gravitational field. In other words, it's not nothing and we still don't know what caused it.

Thanks that makes sense.

What I can't figure out is how does having a swirl on the microwave background signifying inflation appear on our universe when essentially it is closed to the quantum field.